• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.188-197
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• 2016

In this paper, we propose a method that represents a mathematical form of wave propagation by using the fact the refractive index determining wave propagation characteristic is a function of altitude. Proposed method uses Snell's law that expresses relationship between incident angle and refraction angle when incident wave passes medium having a different refractive index. We present the simulation results about wave propagation by setting the square of refractive index in the form of the polynomial for altitude and show that it is possible to estimate the coefficients of the polynomial through the angle information from vertical axis of multiple radar systems.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.3
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• pp.191-201
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• 2014

Marine algal flora and community structure were investigated seasonally at three sites in subtidal zone of Wangdol-cho on the east coast of Korea from May 2012 to August 2013. A total of 122 species were collected and identified, including 12 green algae, 29 brown algae, and 81 red algae. Of these, 38 species were found throughout the survey period. Average seaweed biomass was 472.19-1,198.77 g wet wt. $m^{-2}$ in spring, 68.99-631.14 g wet wt. $m^{-2}$ in summer, 200.91-401.20 g wet wt. $m^{-2}$ in autumn, and 53.61-922.32 g wet wt. $m^{-2}$ in winter. The vertical distribution based on biomass were Grateloupia lanceolata, Acrosorium venulosum, Lomentaria catenata - Undaria pinnatifida, Dictyopteris pacifica, Sargassum horneri, Ecklonia cava - Desmarestia viridis, E. cava, S. horneri from upper to lower subtidal zone. The flora was classified into six functional groups: filamentous form (34.43%), coarsely branched form (25.41%), sheet form (24.59%), thick leather form (9.71%), crustose form (5.74%) and jointed calcareous form (0.82%). The C/P, R/P and (R+C)/P values reflecting the flora characteristics were 0.41, 2.79 and 3.21, respectively. Also, diversity index (H') and dominance index (DI) indicate that the algal community and environmental condition of Wangdol-cho is stable. We recommend that Wangdol-cho subtidal zone should be more protected from human activities such as turbulence and eutrophication in order to maintain species diversity and abundance of algae.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.2
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• pp.273-285
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• 1992

The purpose of this study was to evaluate facial form, arch form and tooth form in young adults to determine if a correlation exists. 115 subjects who had healthy natural maxillary incisors and good occlusion consisted of 71 males and 44 females ranging from 20-30 years of age. Facial photographs and, intraoral photographs of upper anterior teeth and dental casts of upper jaws were taken to demonstrate facial form, dental arch form and tooth form. Form analysis is determined by comparing the ratio of the widths of the faces, dental archs and the teeth. The Chi-square test of independence between facial form, arch form and tooth form, was executed and the significance level determined. The results were as follows : 1. The distribution of facial forms was 66.1% square-tapering, 27.0% square, 5.2% ovoid, 2% tapering-square. 2. The distribution of tooth forms was 65.2% ovoid, 20.0% square-tapering, 11.3 % tapering-square, 3.5 % square. 3. The distribution of arch forms was 50.4 % square-tapering, 48.7 % tapering, 0.9 % reverse tapering-square. 4. There was no large differences in the distribution of facial forms, dental arch forms and tooth-forms between male and female. 5. No relationship existed between the tooth form and the facial form. 6. No relationship existed between the facial form and the dental arch form. 7. No relationship existed between the tooth form and the dental arch form. 8. This gave the impression that dental arch form and facial form could not be used as a true index in tooth selection.

• Structural Engineering and Mechanics
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• v.67 no.4
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• pp.417-425
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• 2018

The main aim of this paper is to investigate the bending of Euler-Bernouilli nano-beams made of bi-directional functionally graded materials (BDFGMs) using Eringen's non-local elasticity theory in the integral form with compare the differential form. To the best of the researchers' knowledge, in the literature, there is no study carried out into integral form of Eringen's non-local elasticity theory for bending analysis of BDFGM Euler-Bernoulli nano-beams with arbitrary functions. Material properties of nano-beam are assumed to change along the thickness and length directions according to arbitrary function. The approximate analytical solutions to the bending analysis of the BDFG nano-beam are derived by using the Rayleigh-Ritz method. The differential form of Eringen's non-local elasticity theory reveals with increasing size effect parameter, the flexibility of the nano-beam decreases, that this is unreasonable. This problem has been resolved in the integral form of the Eringen's model. For all boundary conditions, it is clearly seen that the integral form of Eringen's model predicts the softening effect of the non-local parameter as expected. Finally, the effects of changes of some important parameters such as material length scale, BDFG index on the values of deflection of nano-beam are studied.

• Geomechanics and Engineering
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• v.24 no.2
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• pp.167-178
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• 2021

Spatial variability is an inherent uncertainty of soil properties. Current reliability analyses generally incorporate random field theory and Monte Carlo simulation (MCS) when dealing with spatial variability, in which the computational efficiency is a significant challenge. This paper proposes a KL-FORM algorithm to improve the computational efficiency. In the proposed KL-FORM, Karhunen-Loeve (KL) expansion is used for discretizing random fields, and first-order reliability method (FORM) is employed for reliability analysis. The KL expansion and FORM can be used in conjunction, through adopting independent standard normal variables in the discretization of KL expansion as the basic variables in the FORM. To illustrate the effectiveness of this KL-FORM, it is applied to a case study of a strip footing in spatially variable unsaturated soil under rainfall, in which the bearing capacity of the footing is computed by numerical simulation. This case study shows that the KL-FORM is accurate and efficient. The parametric analyses suggest that ignoring the spatial variability of the soil may lead to an underestimation of the reliability index of the footing.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.3
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• pp.153-165
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• 2021

The objective of this study was to provide basic data for the conservation of wetland ecosystems in the Civilian Control Zone and the management of Yongyangbo wetlands in South Korea. Yongyangbo wetlands have been designated as protected areas. A field survey was conducted across five sessions between April 2019 and August of 2019. A total of 248 taxa were identified during the survey, including 72 families, 163 genera, 230 species, 4 subspecies, and 14 varieties. Their life-forms were Th (therophytes) - R₅ (non-clonal form) - D₄ (clitochores) - e (erect form), with a disturbance index of 33.8%. Three taxa of rare plants were detected: Silene capitata Kom. and Polygonatum stenophyllum Maxim. known to be endangered species, and Aristolochia contorta Bunge, a least-concern species. S. capitata is a legally protected species designated as a Class II endangered species in South Korea. A total of 26 taxa of naturalized plants were observed, with a naturalization index of 10.5%. There was one endemic plant taxon (Salix koriyanagi Kimura ex Goerz). In terms of floristic target species, there was one taxon in class V, one taxon in Class IV, three taxa in Class III, five taxa in Class II, and seven taxa in Class I. Three invasive alien species (Ambrosia trifida L., Ambrosia artemisiifolia L., and Humulus japonicus Siebold & Zucc) were observed. For continuous conservation of Yongyangbo Wetlands, it is necessary to remove invasive alien plants and block the inflow of non-point pollutants.

• The Journal of the Korea Contents Association
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• v.22 no.8
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• pp.115-125
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• 2022

This study examines the effect of performers on the number of views and likes of entertainment show clips consumed on AVOD short form platform. Multiple regression analysis was performed, setting program viewing factors and performer's topicality index as independent variables, and setting the number of views and likes of clips as dependent variables. As a result of the analysis, performer's topicality index had a positive(+) effect on both dependent variables. According to standardized coefficient, on the number of views, the standardization coefficient of the performer's topicality index was the second highest, and on the number of likes it was the highest among variables. The results suggest that performers contribute a lot to the success of clips on AVOD short form platform.

• Steel and Composite Structures
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• v.15 no.4
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• pp.357-377
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• 2013

In order to study the degradation and damage behaviors of steel frame welded connections, two series of tests in references with different connection constructions were carried out subjected to various cyclic loading patterns. Hysteretic curves, degradation and damage behaviours and fatigue properties of specimens were firstly studied. Typical failure modes and probable damage reasons were discussed. Then, various damage index models with variables of dissipative energy, cumulative displacement and combined energy and displacement were summarized and applied for all experimental specimens. The damage developing curves of ten damage index models for each connection were obtained. Finally, the predicted and evaluated capacities of damage index models were compared in order to describe the degraded performance and failure modes. The characteristics of each damage index model were discussed in depth, and then their distributive laws were summarized. The tests and analysis results showed that the loading histories significantly affected the distributive shapes of damage index models. Different models had their own ranges of application. The selected parameters of damage index models had great effect on the developing trends of damage curves. The model with only displacement variable was recommended because of a more simple form and no integral calculation, which was easier to be formulated and embedded in application programs.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.13 no.1
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• pp.72-80
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• 2009

Objective: We performed this study to check relationship of Cold-Heat attribute analyzed quantitatively by questionnaire with acoustic analysis index. Method : We checked a questionnaire composed of 15 items about the contents of Cold-Heat and asked 83 subjects to answer in the form Likert-like 7-points score. And then, we extracted Cold-Heat attribute from heat score, cold score, heat index and cold index. we measured the acoustic analysis indexes of cardinal vowels by Dr. speech program. Afterward, the data were analyzed by correlation analysis. Results : All cardinal vowels is positive correlated with cold score, heat score and cold index. NNE of vowel /a/ is negative correlated with cold index. Shimmer and F0 tremor of vowel /e/ is negative correlated with cold index. Jitter of vower /u/ is positive correlated with Cold score.

• Journal of the Optical Society of Korea
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• v.2 no.2
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• pp.58-63
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• 1998

Cross-talk effects in high-density volume holographic interconnections are investigated using perturbative iteration method of the integral form of Maxwell's wave equation. In this method, the paraxial approximation and negligence of backward scattering introduced in conventional coupled mode theory is not assumed. Interaction geometries consisting of non-coplanar light waves and multiple index gratings are studied. Arbitrary light polarization is considered. Systematic analysis of cross-talk effects due to multiple index gratings is performed in increasing level of diffraction orders corresponding to successive iterations. Some numerical examples are given for first and third order diffraction.